PinePhone Pro/Create a multi-distribution image using rk2aw

This article explains how to create a multi-distribution image on the PinePhone Pro using rk2aw.

Multi-distro on microSD Card

This article explains how to install megi's rk2aw loader, U-Boot to SPI and a multi-distribution image to the microSD card and/or eMMC of the PinePhone Pro. Further instructions regarding rk2aw can be found on megi's website under https://xff.cz/kernels/rk2aw/rk2aw-rk3399-pinephone-pro/INSTALL. Please note that loader and userspace utility to flash it are free, but not open-source.

Flash rk2Aw loader to SPI

Connect PinePhone Pro to a Linux machine, start a ssh connection and download installer to flash pre-loader to the phone's SPI.

ssh <user>@<phoneip>
cd ~/Downloads
curl -O https://xff.cz/kernels/bootloaders/ppp.tar.gz
tar -xvzf ppp.tar.gz -C ~/Downloads
# scp -r ~/Downloads/ppp <user>@<phoneip>:~/Downloads # copy to phone, non needed
cd ppp
sudo ./spinor-flash-initial-setup.sh

Build multi-distro on the microSD card

If necessary wipe the microSD card

sudo dd if=/dev/zero of=/dev/sdb count=1 bs=32768 status=progress # quick way i.e. # 32GB SDcard (30989615104bytes/32768dim=1volta)
sudo dd if=/dev/zero of=/dev/sdb count=945728 bs=32768 status=progress # slow way i.e. # 32GB SDcard (30989615104bytes/32768dim=945728volte)
sudo dd if=/dev/zero of=/dev/sdb count=15271040 bs=4096 status=progress # 63GB SDcard (62550179840bytes/512dim=122168320volte)
sudo shred -n 5 -vz /dev/sdb # 6 scritture 12h x 64gb

Before removing partitions, if you need to remove also left signatures, use gParted and format each partition "cleared". Than remove all partitions with gParted.

sudo wipefs /dev/sdb # shows current signatures
sudo wipefs --all --force /dev/sdb # erase current signatures

Partition the microSD card

Note: A minimum capacity of 64 GB for the microSD card is recommended for 5 distributions.

sudo sfdisk /dev/sdb --wipe always <<EOF
 label: gpt
 first-lba: 64
 table-length: 8
 start=64, size=32704, type=D7B1F817-AA75-2F4F-830D-84818A145370, name="loader", attrs=RequiredPartition
 size=11G, name="ALARM", attrs="RequiredPartition,LegacyBIOSBootable"
 size=11G, name="MANJARO", attrs="RequiredPartition,LegacyBIOSBootable"
 size=11G, name="MOBIAN", attrs="RequiredPartition,LegacyBIOSBootable"
 size=11G, name="PMOS", attrs="RequiredPartition,LegacyBIOSBootable"
 size=11G, name="UT", attrs="RequiredPartition,LegacyBIOSBootable"
 size=+, name="extra", attrs="RequiredPartition,LegacyBIOSBootable"
EOF

Checking that no-one is using this disk right now ... OK
Disk /dev/sdb: 58.25 GiB, 62550179840 bytes, 122168320 sectors
Disk model: SD Card Reader  
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: C44BE2FC-34D6-4DD8-99FC-7FFB75602A79
Old situation:
>>> Script header accepted.
>>> Created a new GPT disklabel (GUID: F71BFBA6-D2C3-4C20-8079-1401B10C724C).
The maximal number of partitions is 8 (default is 128).
 /dev/sdb1: Created a new partition 1 of type 'unknown' and of size 16 MiB.
 /dev/sdb2: Created a new partition 2 of type 'Linux filesystem' and of size 11 GiB.
 /dev/sdb3: Created a new partition 3 of type 'Linux filesystem' and of size 11 GiB.
 /dev/sdb4: Created a new partition 4 of type 'Linux filesystem' and of size 11 GiB.
 /dev/sdb5: Created a new partition 5 of type 'Linux filesystem' and of size 11 GiB.
 /dev/sdb6: Created a new partition 6 of type 'Linux filesystem' and of size 11 GiB.
 /dev/sdb7: Created a new partition 7 of type 'Linux filesystem' and of size 3.2 GiB.
 /dev/sdb8: Done.
New situation:
Disklabel type: gpt
Disk identifier: F71BFBA6-D2C3-4C20-8079-1401B10C724C
Device         Start       End  Sectors  Size Type
 /dev/sdb1         64     32767    32704   16M unknown
 /dev/sdb2      32768  23101439 23068672   11G Linux filesystem
 /dev/sdb3   23101440  46170111 23068672   11G Linux filesystem
 /dev/sdb4   46170112  69238783 23068672   11G Linux filesystem
 /dev/sdb5   69238784  92307455 23068672   11G Linux filesystem
 /dev/sdb6   92307456 115376127 23068672   11G Linux filesystem
 /dev/sdb7  115376128 122167295  6791168  3.2G Linux filesystem
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

Build Arch Linux partition

Mount the image, copy rootfs and bootfs to the partition. You need also to make some changes on some files.

cd ~/Downloads/ppp/distros
wget https://github.com/dreemurrs-embedded/Pine64-Arch/releases/download/20230925/archlinux-pinephone-pro-phosh-20230925.img.xz
xz -v -d -k archlinux-pinephone-pro-phosh-20230925.img.xz && mv archlinux-pinephone-pro-phosh-20230925.img archlinux.img
sudo losetup -P /dev/loop1 archlinux.img
sudo mkdir /mnt/archlinux /mnt/archlinux/boot /mnt/archlinux/root /mnt/archlinuxsd
sudo mount /dev/loop1p1 /mnt/archlinux/boot/ && sudo mount /dev/loop1p2 /mnt/archlinux/root/

sudo dd if=/dev/loop1p2 of=/dev/sdb2 bs=1M status=progress conv=fsync
sudo mount /dev/sdb2 /mnt/archlinuxsd/
sudo scp -r /mnt/archlinux/boot/* /mnt/archlinuxsd/boot
sudo mv /mnt/archlinuxsd/boot/boot.scr /mnt/archlinuxsd/boot/boot.scrORIG
sudo mkdir /mnt/archlinuxsd/boot/extlinux && sudo chmod a=rwx /mnt/archlinuxsd/boot/extlinux && sudo chmod a=rwx /mnt/archlinuxsd/etc/fstab

sudo cat << EOF > /mnt/archlinuxsd/boot/extlinux/extlinux.conf
#/boot/extlinux/extlinux.conf
MENU TITLE Pinephone Pro Boot Menu
LABEL l0
MENU LABEL ALARM
FDT /boot/dtbs/rockchip/rk3399-pinephone-pro.dtb
KERNEL /boot/Image.gz
INITRD /boot/initramfs-linux.img
APPEND root=PARTLABEL=ALARM console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
EOF

sudo cat << EOF > /mnt/archlinuxsd/etc/fstab
# <file system> <dir> <type> <options> <dump> <pass>
PARTLABEL=ALARM	/         	ext4      	rw,relatime	0 1
EOF

Build Manjaro partition

Download, decompress, mount the image. Copy rootfs and bootfs to the partition. You need also to make some changes on some files.

cd ~/Downloads/ppp/distros
wget https://github.com/manjaro-pinephone/phosh/releases/download/beta37/Manjaro-ARM-phosh-pinephonepro-beta37.img.xz
xz -v -d -k Manjaro-ARM-phosh-pinephonepro-beta37.img.xz && mv Manjaro-ARM-phosh-pinephonepro-beta37.img manjaro.img
sudo losetup -P /dev/loop2 manjaro.img
sudo mkdir /mnt/manjaro /mnt/manjaro/boot /mnt/manjaro/root /mnt/manjarosd
sudo mount /dev/loop2p1 /mnt/manjaro/boot/ && sudo mount /dev/loop2p2 /mnt/manjaro/root/

sudo dd if=/dev/loop2p2 of=/dev/sdb3 bs=1M status=progress conv=fsync
sudo mount /dev/sdb3 /mnt/manjarosd/
sudo scp -r /mnt/manjaro/boot/* /mnt/manjarosd/boot
sudo mv /mnt/manjarosd/boot/boot.scr /mnt/manjarosd/boot/boot.scrORIG
sudo mkdir /mnt/manjarosd/boot/extlinux && sudo chmod a=rwx /mnt/manjarosd/boot/extlinux && sudo chmod a=rwx /mnt/manjarosd/etc/fstab

sudo cat << EOF > /mnt/manjarosd/boot/extlinux/extlinux.conf
#/boot/extlinux/extlinux.conf
MENU TITLE Pinephone Pro Boot Menu
LABEL l0
MENU LABEL MANJARO
FDT /boot/dtbs/rockchip/rk3399-pinephone-pro.dtb
KERNEL /boot/Image
INITRD /boot/initramfs-linux.img
APPEND root=PARTLABEL=MANJARO console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
EOF

sudo cat << EOF > /mnt/manjarosd/etc/fstab
# <file system> <dir> <type> <options> <dump> <pass>
PARTLABEL=MANJARO   /   ext4     defaults    0   1
EOF

Build Mobian partition

Download, decompress, mount the image. Copy rootfs and bootfs to the partition. You need also to make some changes on some files.

cd ~/Downloads/ppp/distros
wget https://images.mobian.org/pinephonepro/weekly/mobian-pinephonepro-phosh-20240107.img.xz
xz -v -d -k mobian-pinephonepro-phosh-20240107.img.xz && mv mobian-pinephonepro-phosh-20240107.img mobian.img
sudo losetup -P /dev/loop3 mobian.img
sudo mkdir /mnt/mobian /mnt/mobian/boot /mnt/mobian/root /mnt/mobiansd
sudo mount /dev/loop3p1 /mnt/mobian/boot/ && sudo mount /dev/loop3p2 /mnt/mobian/root/

sudo dd if=/dev/loop3p2 of=/dev/sdb4 bs=1M status=progress conv=fsync
sudo mount /dev/sdb4 /mnt/mobiansd/
sudo scp -r /mnt/mobian/boot/* /mnt/mobiansd/boot
sudo chmod a=rwx /mnt/mobiansd/boot/extlinux && sudo chmod a=rwx /mnt/mobiansd/etc/fstab

sudo cat << EOF > /mnt/mobiansd/etc/fstab
# <file system> <dir> <type> <options> <dump> <pass>
PARTLABEL=MOBIAN	/	ext4	defaults,x-systemd.growfs	0	1
EOF

sudo nano /mnt/mobiansd/boot/extlinux/extlinux.conf
 >adjust ## /boot/extlinux/extlinux.conf file
 >MENU LABEL MOBIAN
 >linux /boot/vmlinuz-6.6-rockchip
 >initrd /boot/initrd.img-6.6-rockchip
 >fdtdir /boot/dtb-6.6-rockchip/
 >APPEND root=PARTLABEL=MOBIAN console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
 ># append root=UUID=b282b619-c9b7-4c15-9c3d-2005b35d5999 consoleblank=0 loglevel=7 ro quiet splash plymouth.ignore-serial>

Ctrl+X to save, Yes, Enter.

Build PostmarketOS partition

For PostMarketOS you can use bootstrap to generate distro image or download image as for the other distros. Make sure you install pmbootstrap before building images

git clone --depth=1 https://git.sr.ht/~postmarketos/pmbootstrap
mkdir -p ~/.local/bin
ln -s "$PWD/pmbootstrap/pmbootstrap.py" ~/.local/bin/pmbootstrap
source ~/.profile # remember to update your environment
pmbootstrap --version # If this returns error, put ~/.local/bin in your PATH, adding the following to your ~/.profile (zsh: ~/.zprofile).
# PATH="$HOME/.local/bin:$PATH" # optional

Create 2GB empty image file, format and mount it.

sudo su
dd if=/dev/zero of=postmarketos.img bs=1 count=0 seek=2G status=progress && sync
mkfs.ext4 postmarketos.img
losetup -P /dev/loop0 postmarketos.img
exit

Build PMOS image via pmbootstrap

pmbootstrap init # follow all the setup directions
pmbootstrap status
pmbootstrap pull
pmbootstrap install --sdcard=/dev/loop0
pmbootstrap shutdown # remember to deactivare chroot after the image creation

Download, decompress, mount the image. Copy rootfs and bootfs to the partition. You need also to make some changes on some files.

cd ~/Downloads/ppp/distros
wget https://images.postmarketos.org/bpo/v23.12/pine64-pinephonepro/phosh/20240103-1352/20240103-1352-postmarketOS-v23.12-phosh-22.3-pine64-pinephonepro.img.xz
xz -v -d -k postmarketOS-v23.12-phosh-22.3-pine64-pinephonepro.img.xz && mv postmarketOS-v23.12-phosh-22.3-pine64-pinephonepro.img postmarketos.img
sudo losetup -P /dev/loop4 postmarketos.img
sudo mkdir /mnt/postmarketos /mnt/postmarketos/boot /mnt/postmarketos/root /mnt/postmarketossd
sudo mount /dev/loop4p1 /mnt/postmarketos/boot/ && sudo mount /dev/loop4p2 /mnt/postmarketos/root/

sudo dd if=/dev/loop4p2 of=/dev/sdb5 bs=1M status=progress conv=fsync
sudo mount /dev/sdb5 /mnt/postmarketossd/
sudo scp -r /mnt/postmarketos/boot/* /mnt/postmarketossd/boot
sudo mkdir /mnt/postmarketossd/boot/extlinux && sudo chmod a=rwx /mnt/postmarketossd/boot/extlinux && sudo chmod a=rwx /mnt/postmarketossd/etc/fstab

sudo cat << EOF > /mnt/postmarketossd/boot/extlinux/extlinux.conf
#/boot/extlinux/extlinux.conf
default l0
menu title U-Boot menu
prompt 0
timeout 10
label l0
 menu label PMOS
 linux /boot/vmlinuz
 initrd /boot/initramfs-extra
 fdtdir /boot/dtbs-pine64-pinephonepro/
APPEND root=PARTLABEL=PMOS console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
EOF

sudo cat << EOF > /mnt/postmarketossd/etc/fstab
# <file system> <mount point> <type> <options> <dump> <pass>
PARTLABEL=PMOS / ext4 defaults 0 0
EOF

Build Ubuntu Touch partition

Download, decompress, mount the image. Copy rootfs and bootfs to the partition. You need also to make some changes on some files.

cd ~/Downloads/ppp/distros
wget https://ci.ubports.com/job/focal-hybris-rootfs-arm64/job/master/lastSuccessfulBuild/artifact/ubuntu-touch-pinephone-pro-img-arm64.raw.xz
xz -v -d -k ubuntu-touch-pinephone-pro-img-arm64.raw.xz && mv ubuntu-touch-pinephone-pro-img-arm64.raw ubuntu.raw
sudo losetup -P /dev/loop5 ubuntu.raw
sudo mkdir /mnt/ubuntutouch /mnt/ubuntutouch/boot /mnt/ubuntutouch/root /mnt/ubuntutouchsd
sudo mount /dev/loop5p2 /mnt/ubuntutouch/boot/ && sudo mount /dev/loop5p3 /mnt/ubuntutouch/root/

sudo dd if=/dev/loop5p3 of=/dev/sdb6 bs=1M status=progress conv=fsync
sudo mount /dev/sdb6 /mnt/ubuntutouchsd/
sudo scp -r /mnt/ubuntutouch/boot/* /mnt/ubuntutouchsd/boot
sudo chmod a=rwx /mnt/ubuntutouchsd/etc/fstab
# sudo chmod a=rwx /mnt/ubuntutouchsd/boot/extlinux
sudo chmod a=rwx /mnt/ubuntutouchsd/boot/extlinux/extlinux.conf

sudo cat << EOF > /mnt/ubuntutouchsd/etc/fstab
# <file system> <dir> <type> <options> <dump> <pass>
PARTLABEL=UT	/	ext4	defaults	0	1
EOF

sudo nano /mnt/ubuntutouchsd/boot/extlinux/extlinux.conf
>adjust ## /boot/extlinux/extlinux.conf file
>menu label UT
>linux /boot/vmlinuz-6.5.0-okpine-ut
>initrd /boot/initrd.img-6.5.0-okpine-ut
>fdtdir /boot/dtb-6.5.0-okpine-ut/rockchip/

>#append root=UUID=9f3cfee6-e7ed-4d4a-bfeb-e54ef502cec7 console=ttyS2,115200n8 consoleblank=0 loglevel=7 ro splash plymouth.ignore-serial-consoles vt.global_cursor_default=0
>APPEND root=PARTLABEL=UT console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait

Unmount and detach all images

sudo umount /mnt/*/* && sudo umount /mnt/* && sudo umount /media/*/*
sudo rm -r /mnt/*/* && sudo rm -r /mnt/* && sudo sudo rm -r /media/*/*
sudo losetup -D

Switching On Device

Options to boot Arch Linux ARM, Manjaro, Mobian, PostmarketOS and Ubuntu Touch

According to rk2aw loader info, to operate your PinePhonePro you can:

Plug in USB power cord. Led blinks: 0.5s on, 0.5s off. Battery is charging.

Press shortly power button. Graphical menu appears, than just press onto the image to boot from.

Press power button longer, led starts to blinks rapidly. Release power button, led blinks N times each second according to the flashed images.

In example:

Led blinks once each second and 1st image is selected
;
Led blinks twice each second and 2nd image is seleted
;
Led blinks triple each second and 3rd image is selected
.
Press shortly to move to next image.

Press longer to boot the selected image. 

In case you hold the power button too long, the device is forced to power off.

Troubleshooting

If device doesn't start, connect serial cable (https://pine64.com/product/pinebook-pinephone-pinetab-serial-console/) to headphone jack, switch off microswitch 6 and start a serial console:

ls /dev/ttyUSB* # check usb address from linux machine
minicom -b 1500000 -D /dev/ttyUSB0

More info about erasing eMMC on https://wiki.pine64.org/wiki/PinePhone_Pro_Developer_Edition#Method_2:_Via_serial_cable

Multi-distro on eMMC

Options to boot Phosh or sxmo

Make sure you boot from the microSD card in your PinePhone Pro as we are going to overwrite the eMMC. Note that below, Arch is booted from the microSD card and the microSD card is listed as the device /dev/mmcblk1.

Flash rk2Aw loader to SPI

Same as above. Note this installs rk2aw and a bootloader to SPI NOR flash. Resulting SPI status is as follow:

# ./rk2aw-spi-flasher 
Machine: Pine64 PinePhonePro (pine64,pinephone-pro)
SPI NOR Flash:
- Total size: 16384 KiB
- Erase block size: 4 KiB
- Write size: 1
- Manufacturer: gigadevice
- Part name: gd25lq128e
- JEDEC ID: 257018

Bootable images currently present in SPI NOR flash:
Idx Header     Off 1      Size 1     Off 2      Size 2     Notes/content
-------------------------------------------------------------------------------
0   0          2048       6144       0          0          (padded) 0='rk2aw'
5   131072     133120     67584      200704     124928     0='U-Boot TPL' 1='U-Boot SPL'
7   524288     526336     147456     673792     124928     0='ddrbin' 1='U-Boot SPL'

Auto-calculated layout for rk2aw dual bootloader scheme:
Area                 Offset     Size      
---------------------------------------------------
rk2aw primary        0          65536     
rk2aw backup         65536      65536     
spl fallback         131072     393216    
spl primary          524288     389120    
itb fallback         913408     2097152   
itb primary          3010560    2097152

Build multi-distro eMMC

In this example we are going to build 2 partitions on the eMMC, the first with Arch/Phosh and the second with Arch/sxmo. We have already downloaded the images from Danct12 and decompressed them.

Mount the images

cd ~/Downloads # enter to directory
sudo su # login with your psw
losetup -P /dev/loop0 archlinux-pinephone-pro-phosh-20230203.img 
losetup -P /dev/loop1 archlinux-pinephone-pro-sxmo-20230203.img 
ls -l /mnt/
mkdir /mnt/phosh
mkdir /mnt/sxmo
mkdir /mnt/phosh/boot
mkdir /mnt/phosh/root
mkdir /mnt/sxmo/boot
mkdir /mnt/sxmo/root
mkdir /mnt/ephosh # e for the partition on the eMMC
mkdir /mnt/esxmo  # e for the partition on the eMMC
mount /dev/loop0p1 /mnt/phosh/boot/
mount /dev/loop0p2 /mnt/phosh/root/
mount /dev/loop1p1 /mnt/sxmo/boot/
mount /dev/loop1p2 /mnt/sxmo/root/

lsblk
NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
loop0          7:0    0     5G  0 loop 
├─loop0p1    259:0    0   122M  0 part /mnt/phosh/boot
└─loop0p2    259:1    0   4.9G  0 part /mnt/phosh/root
loop1          7:1    0   3.5G  0 loop 
├─loop1p1    259:2    0   122M  0 part /mnt/sxmo/boot
└─loop1p2    259:3    0   3.4G  0 part /mnt/sxmo/root
mmcblk2      179:0    0 115.2G  0 disk 
├─mmcblk2p1  179:1    0   122M  0 part 
└─mmcblk2p2  179:2    0 115.1G  0 part 
mmcblk2boot0 179:32   0     4M  1 disk 
mmcblk2boot1 179:64   0     4M  1 disk 
mmcblk1      179:96   0  59.6G  0 disk 
├─mmcblk1p1  179:97   0   122M  0 part /boot
└─mmcblk1p2  179:98   0  59.5G  0 part /
zram0        254:0    0   1.5G  0 disk [SWAP]

Prepare eMMC

dd if=/dev/zero of=/dev/mmcblk2 count=32768 bs=32768 status=progress # overwrite the front to clear any bootloaders

sfdisk /dev/mmcblk2 << EOF
label: gpt
first-lba: 64
table-length: 8
size=32G, name="PHOSH", attrs="RequiredPartition,LegacyBIOSBootable"
size=+, name="SXMO", attrs="RequiredPartition,LegacyBIOSBootable"
EOF

Checking that no-one is using this disk right now ... OK
Disk /dev/mmcblk2: 115.23 GiB, 123731968000 bytes, 241664000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
>>> Script header accepted.
>>> Created a new GPT disklabel (GUID: 7EB4B1E0-5F49-4F30-9F1E-E9E1F305D461).
The maximal number of partitions is 8 (default is 128).
/dev/mmcblk2p1: Created a new partition 1 of type 'Linux filesystem' and of size 32 GiB.
/dev/mmcblk2p2: Created a new partition 2 of type 'Linux filesystem' and of size 83.2 GiB.
/dev/mmcblk2p3: Done.

New situation:
Disklabel type: gpt
Disk identifier: 7EB4B1E0-5F49-4F30-9F1E-E9E1F305D461
Device            Start       End   Sectors  Size Type
/dev/mmcblk2p1     2048  67110911  67108864   32G Linux filesystem
/dev/mmcblk2p2 67110912 241661951 174551040 83.2G Linux filesystem
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

lsblk
 NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
 loop0          7:0    0     5G  0 loop 
 ├─loop0p1    259:0    0   122M  0 part /mnt/phosh/boot
 └─loop0p2    259:1    0   4.9G  0 part /mnt/phosh/root
 loop1          7:1    0   3.5G  0 loop 
 ├─loop1p1    259:2    0   122M  0 part /mnt/sxmo/boot
 └─loop1p2    259:3    0   3.4G  0 part /mnt/sxmo/root
 mmcblk2      179:0    0 115.2G  0 disk 
 ├─mmcblk2p1  179:1    0    32G  0 part 
 └─mmcblk2p2  179:2    0  83.2G  0 part 
 mmcblk2boot0 179:32   0     4M  1 disk 
 mmcblk2boot1 179:64   0     4M  1 disk 
 mmcblk1      179:96   0  59.6G  0 disk 
 ├─mmcblk1p1  179:97   0   122M  0 part /boot
 └─mmcblk1p2  179:98   0  59.5G  0 part /
 zram0        254:0    0   1.5G  0 disk [SWAP]

Build Phosh partition

dd if=/dev/loop0p2 of=/dev/mmcblk2p1 bs=1M status=progress conv=fsync
mount /dev/mmcblk2p1 /mnt/ephosh/
scp -r /mnt/phosh/boot/* /mnt/ephosh/boot
mv /mnt/ephosh/boot/boot.scr /mnt/ephosh/boot/boot.scrORIG

cat << EOF > /mnt/ephosh/etc/fstab
 #/boot/extlinux/extlinux.conf
 #Static information about the filesystems.
 #See fstab(5) for details.
 #<file system> <dir> <type> <options> <dump> <pass>
 PARTLABEL=PHOSH 	/   ext4   rw,relatime	0 1
 # UUID=52CA-6165  /boot vf rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro	0 2

mkdir /mnt/ephosh/boot/extlinux

cat << EOF > /mnt/ephosh/boot/extlinux/extlinux.conf
 #/boot/extlinux/extlinux.conf
 MENU TITLE Pinephone Pro Boot Menu
 LABEL l0
 MENU LABEL phosh
 FDT /boot/dtbs/rockchip/rk3399-pinephone-pro.dtb
 KERNEL /boot/Image
 INITRD /boot/initramfs-linux.img
 APPEND root=PARTLABEL=PHOSH console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
 EOF

Build SXMO partition

We have unmounted all the Phosh devices, so

lsblk
 NAME         MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
 loop0          7:0    0     5G  0 loop 
 ├─loop0p1    259:0    0   122M  0 part 
 └─loop0p2    259:1    0   4.9G  0 part 
 loop1          7:1    0   3.5G  0 loop 
 ├─loop1p1    259:2    0   122M  0 part /mnt/sxmo/boot
 └─loop1p2    259:3    0   3.4G  0 part /mnt/sxmo/root
 mmcblk2      179:0    0 115.2G  0 disk 
 ├─mmcblk2p1  179:1    0    32G  0 part 
 └─mmcblk2p2  179:2    0  83.2G  0 part 
 mmcblk2boot0 179:32   0     4M  1 disk 
 mmcblk2boot1 179:64   0     4M  1 disk 
 mmcblk1      179:96   0  59.6G  0 disk 
 ├─mmcblk1p1  179:97   0   122M  0 part /boot
 └─mmcblk1p2  179:98   0  59.5G  0 part /
 zram0        254:0    0   1.5G  0 disk [SWAP]

dd if=/dev/loop1p2 of=/dev/mmcblk2p2 bs=1M status=progress conv=fsync
mount /dev/mmcblk2p2 /mnt/esxmo/
scp -r /mnt/sxmo/boot/* /mnt/esxmo/boot
mv /mnt/esxmo/boot/boot.scr /mnt/esxmo/boot/boot.scrORIG

cat << EOF > /mnt/esxmo/etc/fstab
# Static information about the filesystems.
# See fstab(5) for details.
# <file system> <dir> <type> <options> <dump> <pass>
PARTLABEL=SXMO /     ext4      	rw,relatime	0 1
# UUID=841C-F9DD      	/boot     	vfat      	rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro	0 2
EOF

mkdir /mnt/esxmo/boot/extlinux

cat << EOF > /mnt/esxmo/boot/extlinux/extlinux.conf
 #/boot/extlinux/extlinux.conf
 MENU TITLE Pinephone Pro Boot Menu
 LABEL l0
 MENU LABEL sxmo
 FDT /boot/dtbs/rockchip/rk3399-pinephone-pro.dtb
 KERNEL /boot/Image
 INITRD /boot/initramfs-linux.img
 APPEND root=PARTLABEL=SXMO console=ttyS2,115200 console=tty0 loglevel=4 rw rootwait
EOF

Follow-up comments

1. On first boot neither Phosh nor sxmo resized their partition - sudo resize2fs sorted that.
2. Any time an update rebuilds the initramfs it is necessary to delete /boot/boot.scr again to keep the rk2aw menu clean.
3. In case you want to reinstall just a single distribution, the easy way is to delete an recreate partition using gParted GUI.